Exclusive: A Peek Inside NASA’s Global Hawk Hangar

Hurricane researchers are enjoying some new capabilities this month thanks to a pair of unmanned Global Hawk aircraft capable of flying for up to 30 hours at a time. Aircraft and satellites have long been used to study and observe hurricanes. The airplanes with pilots and researchers on board are capable of making measurements and getting up close, but only for a maximum of about 10 hours. Satellites could watch them for days, but with limited resolution, and they can't exactly make atmospheric measurements from space.

In 2007 NASA acquired a pair of pre-production Global Hawks (airframes #1 and #6) and entered a partnership with Northrop Grumman to modify, operate and maintain the airplanes as scientific and research platforms and began using them to study hurricanes in 2010. The airplanes are shared 50/50, with each organization getting half of the flight hours and providing half of the funding/manpower for operating and maintenance costs.

NASA's Chris Naftel oversees the Global Hawk program and says the airplanes were well suited for the agency's needs.

"We had a big hole. We had the ER-2 [a modified U-2] and DC-8 that would give us about 10 hours [flight time] at mid altitude," Naftel told Wired. "We had the Predator that would give us more endurance but at lower altitude. Global Hawk bought us a lot of altitude all the way out to 30 hours."

The Global Hawk's ability to fly high and for more than a day at a time made the program an easy sell for NASA management, says Naftel. He adds that the airplanes are purely used as scientific platforms and are funded by the airborne science program.

The initial hurricane observation flights were made from the Global Hawk's home base at the Dryden Flight Research Center, located within Edwards Air Force Base in Southern California. The long commute from California to the Atlantic limited the amount of time the airplanes could spend over a hurricane.

NASA had planned on basing the aircraft on the East Coast during hurricane season, and earlier this month one of NASA's Global Hawks was flown to the agency's Wallops Island facility in Virginia (pictured above) and will soon be joined by the second aircraft. From this new base on the East Coast, the Global Hawks will be able to cover almost the entire area of the mid-Atlantic Ocean, where hurricanes develop, and spend 10 to 20 hours at a time – possibly more – watching the storms develop and tracking them as they cross the ocean towards North America.

We had a chance to walk through the hangar where the Global Hawks are based at NASA's Dryden Flight Research Center. Both airplanes were at various states of modification during our visit in preparation for their current hurricane observation mission.

Photo: NASA

Initially developed for the military by Northrop Grumman, the Global Hawk is a high-altitude observation platform capable of flying up to 65,000 feet with a wide range of instruments on board. The airplanes have flown more than 30,000 hours over Afghanistan and Iraq since first being deployed to a combat zone in October 2001.

Like many unmanned aircraft, the Global Hawk's capabilities have attracted the attention of those beyond the military. Global Hawks were flown more than 300 hours over the areas affected by the earthquake and tsunami in Japan last year, aiding search-and-rescue efforts as well as providing imagery of the nuclear power plant after the meltdown.

Here the first (left) and sixth (right) Global Hawks to roll off the assembly line sit inside a hangar at Dryden. The airplane has a wingspan of 116 feet. The high-aspect-ratio wings are made from composites, and their efficient design is one of the main reasons the airplane can fly for such long periods of time at high altitudes.

Photo: Jason Paur/Wired.com

Because the airplanes were originally designed with military observation in mind, AV-1 and AV-6 underwent significant modifications to prepare them for use as science platforms. The Air Force mostly limited its instruments to under the nose of the Global Hawk. NASA has modified the airplanes, installing power and Ethernet connections throughout the airframes to accommodate payloads from a camera in the nose, to a device that operates sort of like a soda-can machine, dropping atmospheric measuring devices out the tail.

Without the fairing that covers the nose, it's possible to see the platform where the Ku-band antenna dish resides in the front of the Global Hawk. On this airplane (airframe #1, tail number 871), the nose area where cameras would normally be found on a military version will be filled with the Cloud Physics Lidar. This instrument will allow researchers to see cloud structure and depth within the hurricane.

Photo: Jason Paur/Wired.com

Here the top of the Cloud Physics Lidar instrument can be seen directly in front of the Global Hawk's Ku-band communication antenna.

Photo: NASA

Here's a view from the other side of 871. The airplane was the first Global Hawk built and NASA will use it to carry the "environmental payloads" for hurricane research. In addition to the cloud lidar, the airplane will carry other instruments that will make direct measurements of the hurricanes as they develop.

The Global Hawk is powered by a single Allison Rolls Royce turbofan engine capable of producing just over 7,000 pounds of thrust. The airplane has a maximum take-off weight of 26,750 pounds and typically cruises at around 370 miles per hour.

Photo: Jason Paur/Wired.com

NASA had to modify the Global Hawks significantly to accommodate scientific payloads. This included adding mounting brackets throughout the airframe as well as the electrical power and Ethernet connections for the instruments.

Photo: Jason Paur/Wired.com

Many of the airplane's internal bays are filled with communication and data-management equipment. And a well-strapped-in mascot. Tail number 872 is nicknamed Mr. Bill, and the adventurer goes along for the flights. The other airplane is called Yoda – named after the call sign of a pilot who first flew the Global Hawk – and also will fly with its namesake on board.

Photo: Jason Paur/Wired.com

NASA isn't using the same cameras and other observation/spy equipment the military uses on its own Global Hawk aircraft. But there are a few cameras on board, like this one in the nose that is used primarily for simply seeing where the airplane is going during flights. It's the eyes for the pilots, especially important during take-off and landing.

Tail number 872 was the sixth Global Hawk to roll off the Northrop Grumman assembly line and will serve as the "big picture" platform during the hurricane missions. The airplane will carry three main scientific instruments and will not get as close to the storms as 871.

Never an agency to shy away from big names, 872's nose carries the High Altitude Monolithic Microwave Integrated Circuit Sounding Radiometer. It allows scientists to take temperature measurements as well as profiles of the liquid water content in the clouds. The belly of 872 carries the High Altitude Imaging Wind and Rain Airborne Profiler to measure radar reflectivity (rain) and wind speeds. In the tail measurements of surface wind speeds and rain rate will be measured from the Hurricane Imaging Radiometer.

Photo: Jason Paur/Wired.com

Because of the high-aspect-ratio wings (they're relatively narrow compared to their span), the Global Hawk has an excellent glide ratio. This translates to being able to fly at high altitudes without requiring a tremendous amount of power. But it also means the airplane is a great glider, and like gliders, it can be difficult to descend.

The Global Hawk uses spoilers in the wings to help destroy some of the lift generated when it's time to come down and land. These devices are common on gliders and can also be seen on airliners, usually once the airplane has touched down and the pilot wants to keep it on the ground and slow down.

Photo: Jason Paur/Wired.com

Most of the tail of 871 was missing during our visit. But this is where the business end of the airplane's Airborne Vertical Atmospheric Profiling System will be located. The device will carry 89 dropsondes towards the middle of the airplane, and it operates a bit like a soda machine to transfer the small canisters to the tail, where they will be dropped from the airplane. Each dropsonde will descend attached to a small parachute through the hurricane, measuring wind speed, temperature, humidity and air pressure the whole way down.

These devices are common in other research aircraft and the information is sent back to researchers to develop vertical profiles of the atmosphere in storms.

Photo: Jason Paur/Wired.com

The NASA Global Hawks are flown from the agency's airport on Wallops Island. The airplanes are pre-programmed to fly autonomously over the hurricanes, but pilots can intervene at any time from their ground station to either accommodate a request from a scientist or to avoid the most dangerous parts of the hurricane.

NASA operates a mobile command station at Wallops Island because pilots must be within line-of-sight of the airplanes during take-off and landing operations. Once at cruise altitude over the ocean, the Wallops Island pilots hand over to a flight crew at Dryden, where pilots fly most of the mission.

Photo: NASA

Inside the flight operations room at Dryden sits the mission manager (facing panel at left), along with the pilots to his right. Scientists are also in communication with the flight crew during the missions and can change or add to a flight when needed.

Photo: NASA

Both airplanes will remain at Wallops Island until early October, flying regularly over the Atlantic to study hurricanes. The airplanes will return to their hangar in California for maintenance once they are done, but will be back in Virginia next year for hurricane season, as well as 2014.